The present invention is directed toward a shellfish dredge and more particularly toward a dredge for harvesting surf clams, quohogs and the like.
Apparatus which is presently in use for collecting clams or other shellfish from the bottom of the sea includes a dredge having a knife adjacent the forward end thereof which is adapted to cut through the sand at the bottom of the sea. Located in front of the knife are a plurality of nozzles which inject water under a pressure of approximately 125 pounds into the sand to soften the ocean bottom before the knife cuts therethrough. In order to provide such water pressure, pumps must be carried by the ship and long hoses having diameters of between 6 and 10 inches must be connected between the dredge and the ship.
The use of this high pressure water forces a great deal of sand into the clams. As a result, the majority of the clams which go under the knife and are not picked up by the dredge are destroyed by the sand forced into them thereby destroying the clam bed. Furthermore, even those clams which are harvested have a great deal of sand in them. This causes particular problems for the undersized clams which are brought up onto the deck of the ship by the dredge and which must be thrown back into the ocean since only clams of 5 inches or larger can be harvested. The smaller clams, being full of sand, normally will die. It is estimated that only about 25 percent of available clams are harvested and the remainder which could be harvested die from being smothered.
There have been proposals in the past for seafood dredges which do not utilize high pressure water. All of these devices generally include a single row of downwardly depending teeth located in front of a collection bag or cage. Examples of such devices are shown in U.S. Pat. Nos. 1,413,944; 3,608,217 and 4,112,602.
To applicant's knowledge, none of these proposed devices have ever been successfully commercialized. With a single row of teeth, the teeth must be relatively close together in order to pick up the clams or other shellfish. However, this makes it substantially more difficult to pull the dredge through the sand since clam beds are normally quite compact and must be broken up by the teeth. Furthermore, these prior devices have not provided efficient means for preventing damage to the teeth in the event that the dredge encounters a rock bed or the like. This is due to the fact that the bottom of the teeth are the lowermost part of the dredge and are, therefore, the first to encounter rocks or similar obstructions.